Sound-amplifier for phonographs.



W. C. FREEMAN.

SOUND AMPLIFIER FOR PHONQGRAPHS.

APPLICATION FILED 1mm. 1918.

1,285,668. Patented Nov. 26, 1918.

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within the cabinel; and is located W'IFLLIAM 3. FEEEllir-"illl,

SQUEFD'AMPLEEIEZEL FOIL @l i Fllllll s. v Specification Letters Patent,

Application riled To all whom it may concern Be it known that l, l IILLIAM. 4 q a cl izen of the Slates Nashville, in the county of llaxa-idson and State of Tennessee have invented and useful lmprovemenbs in Soru1d+linplifiers for Phonogrophs, of which the following a. specification.

This invention relates to sound amplifiers for phonographs and the like, and more par- ;icularly to phonographs oi roar kind com-- inonly known as the cabinet type and wherein the sound'chamber or amplifier is inclosed below the turntable-for a record of the liar. disk type. Among the objects or my invei'ition is to improve the construction of sound amplifiers of the hind referred to in the several. particulars as will hereinafter more fully appear, and loprovidc, in. particular sound chanr ber or amplifier of such ace;- struclion that will not only enhance the strength, volume. and vquality of izhe sound conveyed thereto from the tone arm but will also eliminate the abrasive sounds caused by the travel. of the stylus over the record. and also all such foreign noises as nasal sounds and the like which have heretofore been rendered marl;- edly audible when playing phonographs as heretofore made. Furthermore, with my improved sound chamber or amplifier it is possible when rendering a selection. whether instrumental or otherwise, to produce a tone as true and as natural as the tone of the selection when originally produced. in lhe making of the master recor l.

in carrying out the objcc'lso-f my invenlion 1 provide in general a hollow sound chamber or amplifier or the tapered type and provide wiihin such. chamber adjacent rho end connnunicating with the conduit the tone arm, a plurality of oppositely disposed plates of orlilre sound-conduciing material, so as to increasethe strength of the tone of the soundconveyed to such chamber through the tone arm. ln order to present the greatest possible amount of resonance and volume to the sound, 1 pro ride several metallic plates arranged opposite each other and located one on each side of said glass plates, and, furthermore, surround each or such plates with resilient ma terial, such as rubber, which material serves to deflect the sound waves within the sound $erial No. 213,862.

lim'l'en'leal Flow 26., 1%18.

box and neulralize the abrasive. nasal. and other foreign sounds likely to be produced in she playing oi a record, to such an extent as in make the same not audible and thus completely eliminate the same.

The invention consists further in the matrein-site described and more particuy poinied out in the appended claims. i the accompanying (,lra\\'ingsgure is a vertical sectional View taken through The cabinet of a phonograph and showing; Znerem, in elevation. a hollow sound chamber or amplifier consl'rlwted in accordance with my invention;

Fig. 2 is a View looking into said sound chamber or amplifier from the outer or sectional View taken Fig, l is like View of another of such walls: and

F g 11 1s a vertical sectional View taken on line .l.l-ll of Fig. 3.

In Fig. l of the drawings, l have shown :3. hollow sound chamber or amplifier constructed in accordance with my invention and installed in a phonograph of the cabinet type, the latter having a front wall ll, a rear wall 12, a top wall 13. side walls 13, and an interior partition wall 11. which sepointes the compartment in which the amplilicr ll) is located from the compartment iherebclow. Said sound amplifier 10 is-madc tubular in form, and in the example shown is substantially rectangular in crosssect-i0n. in addition, said amplifier is tapered lengthwise with both ends open. the larger end be.- ing the outer end thereof and opening outwardly through a. grille 15 provided in said front wall 11. The inner or smaller end of said sound chamber or amplifier 10 abuts inst she opposed end of a conduit or/pipe opens thereinto, as customary in.

phonograph construction. The upper end of said 'plpe 16 commumcates with a swinging tone arm 17 located above the top wall 13. Alsoabove said top wall 13 is a turntable 18, mounted on a vertical shaft or spindle 19 extending downwardly through said top wall and suitably connected with a. mo-

. tor (not shown) provided in the cabinet for lrecord 21 when placed on said turn-table.

So much of the construction described is provided generally in all phonographs of the type referred to, and forms no part of my present invention, but has merely been described and shown for the purpose of illustrating the manner in which my improved sound chamber or amplifier 10 isapplied thereto. I

Referring to my improved sound chamber or amplifier 10, the same comprises two. alined partsor sections 22 and 23, which parts when placed together in a phonograph cabinet or the like, form the complete sound chamber or amplifier, as clearly shown in Fig. 1. The section 22 is the forward one,

and is positioned adjacent the grille 15, while the section 23 is the rearward one and extends between the forward section and the conduit 16. The sections are placed together in alinement, as shown, with their meeting ends abutting. The forward seccypress, and comprises four connected walls, there being a top wall 24, a bottom wall 25, and two side walls 26, 26. Said walls are so arranged that the grain of the wood runs transversely across the amplifier 10, as

- clearly shown in Fig. 1. The rearward section 23 is also made of wood. and comprises four connected walls;a top wall 27, a bottom wall 28, and two side walls 29, 29, all of such walls forming continuations of the corresponding walls of the forward section The'walls of the rearward section 23 are made'of wood, the grain of which may run lengthwise of the sound amplifier, as clearly I preferably made of iron and of a size less than that ofthe inner surface of such wall, as shown in Figs. 2, 4:, 8, and 9. Said metal plate 30 has a uniform-thickness throughout, and is centrally locatedwith respect to the margin of the wall to which t. is secured,

as for instance by screws 31, 31.- Surrounding the margin of said metal plate 30 is a strip of resilient material, such as rubber 32,

which in the instance shown is made in one integral piece, but separate pieces of rubber may be used if found desirable. The rubber strip 32 is as' wide as the distance between the spaced 'edgesgof the metal plateand the outer edges of the wall to which the latter is secured, and, furthermore, has a thickness equal to that of the metal plate 30, so that one is substantially flush with the other.

The top and bottom walls 27, 28 are alike inconstruction, .and when in asound amplifi r, the metal plates and surrounding rubber strips are directly. opposite each other, as best shown in Figs. 2 and 3.

Applied against the .inner face of each side-wall 29, 291s a fiat plate of glass 33 or other like sound-conducting material. Said glass plate 33 is of a. size less than that of the inner surface of said wall 29, and is centrally located with respect to the margin of said wall 29. In the example shown, said glass plate is secured to said wall 29 by an adhesive. Surrouniding the edges of said glass plate 33 is .a fiat strip 34 made of the same kind of rubber or like material as the strip 32. When the walls 29 are in the sound amplifier, the plates of glass 33 are directly opposite each other, as shown in Figs. 2 and4. The-rubber strips 32, 34 are secured to the walls of the rear section 23 in any desired manner, as for instanceby an adhesive. As shown in Fig. 11, the side walls 29, 29 of the rearward section have their upper and lower edges bearing against the top and bottom walls 27, 28, the rubber strips 32 on said top and bottom walls being made of such width as to extendv across I such edges of the side walls. tiorr 22 is made of wood, preferably red The object of making the sound chamber or amplifier 10 tapered is of course to amplify or magnify the sound conveyed into the same by the conduit 16 and tone arm 17, asusual in phonograph construction. Sound amplifiers as heretofore .constructed have:.

like sounds of the voice when a song record is being played. Such nasal sounds seem. to be produced to a more marked extent especially when playing those selections rendered by singers -having high pitched -voices, such as. soprano, tenor, and the like. These objectionable sounds, or foreign noises as they may be called, are rendered audible even when playing the finest selections of which is no doubt due to the fact, that the sound amplifiers as heretofore lfc'onstwucted the best artists on the more costly; records,

the like, comprising two oppositely disposed metallic plates, two plates of a sound-conducting material arranged on opposite sides of said metallic plates, and rubber strips infterposed between the opposed edges. of said plates.

- 3. A sound amplifier for phonographsand the like, comprising two oppositely disposed metallic plates, two plates of glass or, the

like, and strips made of a resilient material interposed between the opposed edges of said, plates.

4. A sound amplifier for phonographs and the like, comprising a plurality of connected walls, at least one of said walls being pro vided with a plate of glass, andanother of said walls being provided with a plate of metal, and strips of resilient material secured to said Walls and surrounding the edges of said plates. 5. A sound amplifier for phonographs and the like, comprising four connected walls, two of said walls each being provided with a late of glass and the remaining two of said walls each being provided witha metal plate, the walls having the glass plates being-arranged opposite each other, and the 40 walls having the metal plates being ar ranged opposite each other, and rubber strips secured to each of said walls and surrounding the edges of said plates.

\6. A sound amplifier for phonographs and the like. comprising two alin'ed sections, one

forming a continuation of the other, one

surrounding the edges of the plate secured thereto.

7. A sound amplifier forphonographs and the like, comprising two alined sections, one being made of wood, and the other section consisting of tour connected Walls, two of which each being provided with a glass plate and the two remaining walls each be ing provided with a metal plate, the walls having the glass plates being arranged opposite each other and the walls having the metal plates being arranged opposite each other, and each of said walls having secured thereto a rubber strip surrounding the edges of the plate secured to such wall.

8. A sound amplifier for phonographs and the like, comprising two alined sections, one being made of wood such as red cypress,

and the other section comprising two oppositely disposed. metallic plates, two plates of sound-conducting material arranged on opposite sides of said metallic plates, and means madeof resilient material interposed between the opposed edges of said plates.

In testimony that I claim the foregoing as my invention, I affix my signature in the presence of two witnesses, this 15th 'day of January, A. D. 1918.

WILLIAM C. FREEMAN.

Witnesses TILLIAM. PAUL STEWART, JonN Fos'rnn JOYNER. 

